Determining the position of a mobile device in an indoor environment

ABSTRACT

Technologies and implementations for determining the location of a device in an indoor environment are generally disclosed.

BACKGROUND

Unless otherwise indicated herein, the approaches described in thissection are not prior art to the claims in this application and are notadmitted to be prior art by inclusion in this section.

For several purposes, it may be desirable to determine the location of amobile device in an indoor environment. Current techniques fordetermining the location of a mobile device may include using a GlobalPositioning System (GPS). Such techniques may be unreliable andineffective in an indoor environment.

SUMMARY

In various embodiments, the present disclosure describes example methodsfor determining a position of a mobile device. Example methods mayinclude receiving, via a mobile device, a wide-band transmission havingdistributed traffic symbol portions, distributed pilot symbol portions,and intermittent punctured pilot symbol portions from at least one basestation of three or more base stations, determining a first path portionof the wide-band transmission associated with a first time delay basedon the intermittent punctured pilot symbol portions such that a secondpath portion of the wide-band transmission is associated with a secondtime delay, determining a distance between the mobile device and the atleast one base station based on the first time delay, and determining alocation of the mobile device based on the determined distance.

In various embodiments, the present disclosure also describes examplemobile handset apparatuses. Example mobile handset apparatuses mayinclude a housing, an antenna located within the housing, a firstanalog-to-digital converter operably coupled to the antenna, a secondanalog-to-digital converter operably coupled to the antenna such thatthe second analog-to-digital converter has an operating speed greaterthan the first analog-to-digital converter, and a processor operablycoupled to the first and second analog-to-digital converters such thatthe processor is configured to switch between the first and secondanalog-to-digital converters so as to process distributed traffic symbolportions and/or distributed pilot symbol portions of a wide-bandtransmission transmitted from at least one base station of three or morebase stations via the first analog-to-digital converter, and so as toprocess intermittent punctured pilot symbol portions of the wide-bandtransmission via the second analog-to-digital converter.

In various embodiments, the present disclosure also describes examplearticles. Example articles may include a signal bearing mediumcomprising machine-readable instructions stored thereon, which, ifexecuted by one or more processors, operatively enable a computingdevice to receive, via a mobile device, a wide-band transmission havingdistributed traffic symbol portions, distributed pilot symbol portions,and intermittent punctured pilot symbol portions from at least one basestation of three or more base stations, determine a first path portionof the wide-band transmission associated with a first time delay basedon the intermittent punctured pilot symbol portions such that a secondpath portion of the wide-band transmission is associated with a secondtime delay, determine a distance between the mobile device and the atleast one base station based on the first time delay, and determine alocation of the mobile device based on the determined distance.

The foregoing summary may be illustrative only and may not be intendedto be in any way limiting. In addition to the illustrative aspects,embodiments, and features described above, further aspects, embodiments,and features will become apparent by reference to the drawings and thefollowing detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

Subject matter is particularly pointed out and distinctly claimed in theconcluding portion of the specification. The foregoing and otherfeatures of the present disclosure will become more fully apparent fromthe following description and appended claims, taken in conjunction withthe accompanying drawings. Understanding that these drawings depict onlyseveral embodiments in accordance with the disclosure and are,therefore, not to be considered limiting of its scope, the disclosurewill be described with additional specificity and detail through use ofthe accompanying drawings.

In the drawings:

FIG. 1 is an illustration of a block diagram of an example system fordetermining the location of a device;

FIG. 2 is an illustration of a block diagram of an exampleimplementation for determining the location of a device;

FIG. 3 is an illustration an example graph of received power over timeat a device;

FIG. 4 is an illustration of a flow diagram of an example method forproviding a location of a device;

FIG. 5 is an illustration of a chart of an example wide-bandtransmission;

FIG. 6 is an illustration of an example device;

FIG. 7 is an illustration of an example computer program product; and

FIG. 8 is an illustration of a block diagram of an example computingdevice, all arranged in accordance with at least some embodiments of thepresent disclosure.

DETAILED DESCRIPTION

Subject matter is particularly pointed out and distinctly claimed in theconcluding portion of the specification. The foregoing and otherfeatures of the present disclosure will become more fully apparent fromthe following description and appended claims, taken in conjunction withthe accompanying drawings. Understanding that these drawings depict onlyseveral embodiments in accordance with the disclosure and are,therefore, not to be considered limiting of its scope, the disclosurewill be described with additional specificity and detail through use ofthe accompanying drawings.

The following description sets forth various examples along withspecific details to provide a thorough understanding of claimed subjectmatter. It will be understood by those skilled in the art, however, thatclaimed subject matter may be practiced without some or more of thespecific details disclosed herein. Further, in some circumstances,well-known methods, procedures, systems, components and/or circuits havenot been described in detail in order to avoid unnecessarily obscuringclaimed subject matter.

In the following detailed description, reference is made to theaccompanying drawings, which form a part hereof. In the drawings,similar symbols typically identify similar components, unless contextdictates otherwise. The illustrative embodiments described in thedetailed description, drawings, and claims are not meant to be limiting.Other embodiments may be utilized, and other changes may be made,without departing from the spirit or scope of the subject matterpresented here. It will be readily understood that the aspects of thepresent disclosure, as generally described herein, and illustrated inthe Figures, can be arranged, substituted, combined, and designed in awide variety of different configurations, all of which are explicitlycontemplated and make part of this disclosure.

This disclosure is drawn, inter alia, to methods, devices, systems andcomputer readable media related to determining the location of a devicein an indoor environment.

In some examples, a location of a device, such as a mobile device, in anindoor environment may be determined. In some examples, the mobiledevice may receive a wide-band transmission transmitted from at leastone base station of three or more base stations. In some examples, thewide-band transmission may include distributed traffic symbol portions,distributed pilot symbol portions, and intermittent punctured pilotsymbol portions. In general, the intermittent punctured pilot symbolportions may provide additional pilot symbol portions that may be usedto determine a shortest path portion of the wide-band transmission,where the wide-band transmission may include two or more path portionsrelated to a multipath effect of the wide-band transmission. In someexamples, the shortest path portion may represent a substantially directpath between the transmitting base station and the mobile device. Insome examples, a time delay related to the shortest path portion may bedetermined based on the received intermittent punctured pilot symbolportions. Such a time delay may be used to determine a distance of theshortest path portion, which may be used to determine the location ofthe mobile device using triangulation techniques, or the like.

FIG. 1 is an illustration of a block diagram of an example system 100for determining the location of a device, arranged in accordance with atleast some embodiments of the present disclosure. As shown, system 100may include a device 110, a base station 120, a base station 130, and abase station 140. In general, device 110 may be any suitable device. Insome examples, device 100 may be a laptop computer, a mobile phone, asmartphone, a netbook device, a tablet device, a personal digitalassistant, or the like. In general, base stations 120, 130, 140 may beany suitable devices. In some examples, base stations 120, 130, 140 mayinclude an access points, a femtocell, or the like.

In general, device 110 and base stations 120, 130, 140 may communicateusing any suitable communications techniques or protocols. In someexamples, device 110 and base stations 120, 130, 140 may communicateusing wide-band multi-tone signaling techniques. In some examples,device 110 and base stations 120, 130, 140 may communicate usingwide-band multi-tone signaling techniques such that the transmittedsignal may include about 2⁹ sinusoidal sub-carriers to about 2¹⁵sinusoidal sub-carriers. In some examples, device 110 and base stations120, 130, 140 may communicate using orthogonal frequency-divisionmultiplexing (OFDM) techniques, code division multiplexing algorithm(CDMA) techniques such as those implemented using the CDMA2000 family ofstandards, 3rd generation (3G) communications techniques, 4th generation(4G) communications techniques, long-term evolution (LTE) communicationstechniques, or the like.

In general, device 110 may determine the location of device 110 usingsignals received from base stations 120, 130, 140. In some examples,device 110 may receive a wide-band transmission transmitted from one ormore of base stations 120, 130, 140. In some examples, device 110 maydetermine the distance between device 110 and base station 120 bydetermining a time-of-arrival for a signal sent from base station 120 todevice 110 and multiplying the time-of-arrival by the speed of light (ora similar speed based on an expected speed of travel of the sentsignal). As is discussed further herein, in some examples, determiningthe time-of-arrival and/or distance may include determining a pathportion of a multiple number of path portions such that the determinedpath portion has the shortest time-of-arrival and/or distance. Suchmultipath portions may be caused by a multipath effect based on objectsbetween base station 120 and device 110, for example.

Device 110 may similarly determine the distances between device 110 andbase station 130 and base station 140. In some examples, the determineddistances may be used to determine the location of device 100 throughtriangulation techniques. In some examples, the path from device 110 toone or more of base stations 120, 130, 140 may not include a multipatheffect. As discussed, in some examples, and, in particular, in indoorenvironments, a signal sent from one or more of base stations 120, 130,140 may have a multipath effect.

FIG. 2 is an illustration of a block diagram of an exampleimplementation 200 for determining the location of a device, arranged inaccordance with at least some embodiments of the present disclosure.FIG. 2 may illustrate an implementation in which the line-of-sightmultipath may be much weaker in power than a later-arriving multipath.As shown, implementation 200 may include a device 110 and a base station120 implemented in an indoor environment 250. In general, indoorenvironment 250 may include any indoor environment such as, for example,an airport, a mall, an office, a home, or the like. In general, thetechniques and/or devices discussed herein may determine the location ofdevice 110. Device location information may be desirable in a wide rangeof applications such as, for example, providing advertisers the locationof a device for location-sensitive ads or coupons, providing a remotedevice the users location such that a friend may meet the user of thedevice, for use in mapping applications, or the like.

As shown, in some examples, a transmission from base station 120 mayhave a multipath effect such that the transmission may include a directpath 230 and a reflected path 240. In general, direct path 230 and/orreflected path 240 may be considered path portions of the transmission.In some examples, direct path 230 and/or reflected path 240 may be pathportions of a wide-band transmission, as is discussed further herein. Insome examples, direct path 230 may be a first path portion and reflectedpath 240 may be a second path portion of a wide-band transmission. Insome examples, direct path 230 may be attenuated or shadowed, or thelike. In some examples, direct path 230 may be attenuated by obstaclessuch as walls, or the like. In some examples, direct path 230 may beattenuated such that a direct path signal related to direct path 230received at device 110 may have less power than a reflected path signalrelated to reflected path 240. As will be appreciated, in general directpath 230 may have a shorter time-of-arrival or time delay than thetime-of-arrival or time deal reflected path 240, however, the arrival ofdirect path 230 may be difficult to detect due to the discussedattenuation of direct path 230. As shown, in some examples, atransmission may have two path portions. In general, a transmission mayhave any number of path portions.

FIG. 3 is an illustration an example graph 300 of received power overtime at a device, arranged in accordance with at least some embodimentsof the present disclosure. As shown, graph 300 may include a profile 310related to a received power over time at a device, such as device 110.In some examples, profile 310 or portions of profile 310 may beconsidered a power-delay profile. Profile 310 may include a peak 330related to receiving a signal related to direct path 230 of FIG. 2 andhaving a related time-of-arrival or delay time 335 and a peak 340related to receiving a signal related to reflected path 240 of FIG. 2and having a related time-of-arrival or delay time 345. As will beappreciated, peak 330 as related to direct path 230 may be related todelay time 335 of the earliest multipath, direct path 230, and, ingeneral, any locations determinations related to device 110 may need touse delay time 335 for an accurate location determinations. Therefore,in general, the triangulation techniques discussed with respect to FIG.1 may require use of peak 330 and/or delay time 335 in determining thedistance between base station 120 and device 110. In general, using peak340 and or delay time 345 in such techniques may provide an inaccuratelocation of device 110.

FIG. 4 is an illustration of a flow diagram of an example method 400 forproviding a location of a device, arranged in accordance with at leastsome embodiments of the present disclosure. In general, method 400 maybe performed by any suitable device, devices, or system such as thosediscussed herein. In some examples, method 400 may be performed by amobile device such as a laptop computer, a mobile phone, a smartphone, anetbook device, a tablet device, a personal digital assistant, or thelike. Method 400 sets forth various functional blocks or actions thatmay be described as processing steps, functional operations, eventsand/or acts, etc., which may be performed by hardware, software, and/orfirmware. Numerous alternatives to the functional blocks shown in FIG. 4may be practiced in various implementations. For example, interveningactions not shown in FIG. 4 and/or additional actions not shown in FIG.4 may be employed and/or some of the actions shown in FIG. 4 may beeliminated, without departing from the scope of claimed subject matter.Method 400 may include one or more of functional operations as indicatedby one or more of blocks 410, 420, 430, and/or 440. The process ofmethod 400 may begin at block 410.

At block 410, “Receive a Wide-Band Transmission from a Base Station viaa Device”, a wide-band transmission may be received via a device. Ingeneral, the wide-band transmission may include any suitable informationand be received using any suitable technique or techniques. In someexamples, the wide-band transmission may be received from one basestation of three or more base stations. In some examples, the wide-bandtransmission may include distributed traffic symbol portions,distributed pilot symbol portions, and intermittent punctured pilotsymbol portions. In general, the distributed traffic symbol portions mayinclude traffic symbols representing the data to be received by thedevice. In general, the distributed pilot symbol portions may includesymbols pre-known to the device that may be used for measuring channelconditions (e.g., equalizer gain, phase shifts, or the like), timesynchronization, frequency synchronization, or the like. In someexamples, the distributed pilot symbol portions may useful fortime-of-arrival estimation techniques discussed herein. In someexamples, the distributed traffic symbol portions and the distributedpilot symbol portions may be distributed amongst each other over timeand/or frequency. In some examples, the distributed traffic symbolportions and the distributed pilot symbol portions may be distributedamongst each other in a pattern known to the receiving device.

In general, the intermittent punctured pilot symbol portions may includesymbols that may replace or puncture traffic symbol portions with pilotsymbol portions as is discussed further herein and, in particular withrespect to FIG. 5. In general, the intermittent punctured pilot symbolportions may be used to determine a time delay and/or distance betweenthe receiving device and the transmitting base station, as is discussedfurther herein. In general, the use of intermittent punctured pilotsymbol portions may provide increased transmission of pilot symbolportions for use in creating a power-delay profile, as is discussedfurther herein. In some examples, the intermittent punctured pilotsymbol portions may include a multiple number of pilot symbolssimultaneously transmitted across a majority of frequencies of thewide-band transmission. In general, the intermittent punctured pilotsymbol portions may puncture any rate of traffic symbols. In someexamples, the intermittent punctured pilot symbol portions may puncturetraffic symbols at a rate ranging from about one punctured pilot symbolin five hundred traffic symbols to a rate of about one punctured pilotsymbol in five thousand traffic symbols. In general, the wide-bandtransmission may include any additional information. As is discussedfurther herein, in some examples the wide band transmission may includepredetermined position information associated with the individual basestations. The process of method 400 may continue at block 420.

At block 420, “Determine a Path Portion of the Wide-Band Transmission”,a path portion of the wide-band transmission may be determined based onthe received intermittent punctured pilot symbol portions. In someexamples, the path portion may include a direct path portion of amultipath effect of the wide-band transmission. In some examples, thepath portion may be a first path portion of the wide-band transmissionsuch that the first path portion of the wide-band transmission may beassociated with a first time delay and a second path portion of thewide-band transmission may be associated with a second time delay asdiscussed herein and, in particular, with respect to FIGS. 2 and 3. Ingeneral, the path portion may be determined using any suitable techniqueor techniques.

In some examples, the path portion may be determined by forming andevaluating a power-delay profile. In some examples, the power-delayprofile may be formed and evaluated based on an evaluation of a multiplenumber of received intermittent punctured pilot symbol portions. In someexamples, the power-delay profile may be determined by determining amatrix that may include an average of the outer-product of the receivedintermittent punctured pilot symbol portions. In some examples, thematrix may be evaluated to determine an eigenvector of the matrix. Insome examples, the determined eigenvector may be used to determinewhether radio energy related to various path portions may have beenreceived at potential arrival time points. Such techniques may indicatea path portion having an attenuated power as discussed herein and, inparticular, with respect to FIGS. 2 and 3. In general, any algorithm maybe used to determine the discussed power-delay profile. In someexamples, the power-delay profile may be determined in part using aMultiple Signal Classification (MUSIC) algorithm. In some examples, thepower-delay profile may be determined in part using an algorithm capableof super-resolvability. In some examples, the power-delay profile may bedetermined in part using a Rayleigh Criterion.

In general, the described techniques may be performed based on anynumber of intermittent punctured pilot symbol portions and/ordistributed pilot symbol portions. In some examples, the accuracy of thetechniques may be improved by using more pilot symbol portions. In someexamples, a duration may be used such that any number of intermittentpunctured pilot symbol portions and/or distributed pilot symbol portionsreceived during that duration may be used. In some examples, theduration may be in the range of about 1 to 5 seconds. In some examples,the duration may be in the range of about 5 to 15 seconds. In someexamples, the duration may be in the range of about 15 to 30 seconds. Insome examples, the techniques may include averaging the results ofevaluating a multiple number of distributed pilot symbol portions. Insome examples, a multiple number of results based on MUSIC algorithmtechniques may be averaged. Such examples, may provide the detection ofmultipaths that may be heavily attenuated, weak, or buried in noise, orthe like.

As discussed, a path portion of a wide-band transmission may bedetermined using the described techniques. In some examples, determiningthe path portion may include determining a path portion and evaluatingan earlier portion of a power-delay profile for another path portionusing a finer sampling technique. In general, such a finer samplingtechnique may be provided in any suitable manner. In some examples, thefiner sampling may be provided using an analog-to-digital converterhaving a greater operating speed as is discussed further herein and, inparticular, with respect to FIG. 6. Referring to FIG. 3, in someexamples, peak 340 and delay time 345 may have been determined using thetechniques discussed herein using a sampling rate. Such a determinationmay have been made during a first determination, for example. As will beappreciated, any earlier peaks related to an earlier multipath may beearlier in time than the determined peak 340. In some examples, a seconddetermination may thereby be made on the portion of profile 310 beforethe time related to peak 340. Such a determination may be made using afiner sampling rate such that peak 330 may be detected using the finersampling rate (although peak 330 may have been, in this example, notdetected during the earlier determination). The process of method 400may continue at block 430.

At block 430, “Determine a Distance Between the Device and the BaseStation”, a distance between the device and the transmitting basestation may be determined. In general, the distance between the deviceand the transmitting base station may be determined using any suitabletechnique or techniques. In some examples, the distance between thedevice and the transmitting base station may be determined based on thedetermined path portion. In some examples, the distance between thedevice and the transmitting base station may be determined based on atime delay related to the determined path portion. In some examples, thedistance between the device and the transmitting base station may bedetermined by multiplying a time delay related to the determined pathportion by the speed of light (or a similar speed based on an expectedspeed of travel of the sent signal). The process of method 400 maycontinue at block 440.

At block 440, “Determine a Location of the Device”, a location of thedevice may be determined. In general, the location of the device may bedetermined using any suitable technique or techniques. In some examples,the location of the device may be determined based on the determineddistance. In some examples, the location of the device may be determinedbased on the determined distance and one or more other distancesdetermined between the device and one or more other base stations. Insome examples, the location of the device may be determined based on atriangulation technique using the determined distance and two otherdistances determined between the device and two other base stations. Insome examples, the location of the device may be determined usingposition data received from one or more base stations. In some examples,the position data may include predetermined position informationassociated with the individual base stations. In some examples, theposition data may be transmitted from one or more of the base stationsat predetermined times.

As discussed, method 400 provides techniques for determining thelocation of a device. In some examples, method 400 may be used in anindoor environment. In some examples, method 400 may be performed at thedevice. In some examples, method 400 or portions of method 400 may beperformed at a base station or other device. For example, the device maydetermine a power-delay profile, a time-of-arrival for a signal, adistance from a base station, or the like and transmit such data toanother device such that the location of the mobile device may bedetermined. Further, when a location of the device has been determined(either at the device or at another device), such information may beused in any suitable manner such as, for example, providing advertisersthe location of a device for location-sensitive ads or coupons,providing a remote device the users location such that a friend may meetthe user of the device, for use in mapping applications, or the like. Ingeneral, such device location information may be transmitted or receivedfor use in any suitable manner.

FIG. 5 is an illustration of a chart 500 of an example wide-bandtransmission 510, arranged in accordance with at least some embodimentsof the present disclosure. As shown, wide-band transmission 510 mayinclude distributed traffic symbol portions 520, distributed pilotsymbol portions 530, and intermittent punctured pilot symbol portions540. As discussed, in general, distributed traffic symbol portions 520may include traffic symbols representing data to be received by a deviceand distributed pilot symbol portions 530 may include symbols pre-knownto the device that may be used for measuring channel conditions (e.g.,equalizer gain, phase shifts, or the like), time synchronization,frequency synchronization, or the like. As shown, in some examples,distributed traffic symbol portions 520 and the distributed pilot symbolportions 530 may be distributed amongst each other over time and/orfrequency. In some examples, distributed traffic symbol portions 520 anddistributed pilot symbol portions 530 may be distributed amongst eachother in a pattern known to the receiving device.

As discussed, in general, the intermittent punctured pilot symbolportions may include symbols that may replace traffic symbol portionswith pilot symbol portions. In general, intermittent punctured pilotsymbol portions 540 may be used to determine a distance between thereceiving device and the transmitting base station, as is discussedfurther herein. In general, intermittent punctured pilot symbol portions540 may be distributed in wide-band transmission 510 in any suitablemanner and at any suitable frequency so long as the receiving device hasan indication of the chosen pattern and/or frequency. As shown, in someexamples, intermittent punctured pilot symbol portions 540 may include amultiple number of pilot symbols simultaneously transmitted across amajority of frequencies of wide-band transmission 510. In some examples,intermittent punctured pilot symbol portions 540 may include a multiplenumber of pilot symbols transmitted across all of the frequencies ofwide-band transmission 510 at a particular time. In some examples,intermittent punctured pilot symbol portions 540 may include a multiplenumber of pilot symbols transmitted at a particular frequencycontinuously over time. In some examples, intermittent punctured pilotsymbol portions 540 may include a multiple number of pilot symbolstransmitted randomly throughout wide-band transmission 510.

In general, wide-band transmission 510 may provide an increase in thenumber of pilot symbol portions available for use in time-of-arrivalestimation techniques such as those discussed herein. Such an increasein the number of pilot symbol portions may reduce the amount ofbandwidth available for distributed traffic symbol portions 520, which,as discussed, carry data. However, such reductions may be substantiallyminor. As discussed, in some examples, a puncturing rate of about onepunctured pilot symbol in five thousand traffic symbols to five hundredtraffic symbols may be used. In such examples, assuming 1,024sub-carriers spaced at 10 kHz, the error rate may be increased by 0.02%to 0.2% (i.e., 1/5000 to 1/500) which may not be a substantial increase.Further, such increased error rates may be substantially mitigatedthrough error-control code techniques, power-control loop techniques, orthe like. In general, the wide-band transmission may include anyadditional information. As is discussed further herein, in some examplesthe wide band transmission may include predetermined positioninformation associated with the individual base stations.

As discussed, intermittent punctured pilot symbol portions 540 may bedistributed in wide-band transmission 510 at any suitable frequency. Insome examples, intermittent punctured pilot symbol portions 540 maypuncture traffic symbols at a rate ranging from about one puncturedpilot symbol in five hundred traffic symbols to a rate of about onepunctured pilot symbol in five thousand traffic symbols. In general,wide-band transmission 510 may have any suitable characteristicsincluding any number of sinusoidal sub-carriers, and symbol portionshaving any suitable duration 560 and/or tone width 570. In someexamples, wide-band transmission 510 may have a number of sinusoidalsub-carriers ranging from about 2⁹ sinusoidal sub-carriers to about 2¹⁵sinusoidal sub-carriers. In some examples, duration 560 may be about 0.1msec and tone width 570 may be about 10 kHz.

As discussed, a power-delay profile may be formed and evaluated todetermine an attenuated multipath portion of a wide-band transmission.In some examples, a higher sampling rate may increase the ability todetermine an attenuated multipath such that a finer sampling maydetermine a finer peak of power over time, as discussed herein and, inparticular, with respect to FIG. 3. Such finer sampling may be made overtime such that a time sampling frequency may be increased. Suchtechniques may detect narrow peaks and finer structures in a powerprofile. In some examples, such increased sampling rates may be providedby including an analog-to-digital converter having a faster operatingspeed.

FIG. 6 is an illustration of an example device 600, arranged inaccordance with at least some embodiments of the present disclosure. Asshown, device 600 may include a housing 610, an antenna 620, ananalog-to-digital converter 630 operably coupled to antenna 620, ananalog-to-digital converter 640 operably coupled to antenna 620, and aprocessor 650 operably coupled to an analog-to-digital converter 630 andan analog-to-digital converter 640. Device 600 may be an exampleimplementation of any device discussed herein. In some examples, device600 may be a laptop computer, a mobile phone, a smartphone, a netbookdevice, a tablet device, a personal digital assistant, or the like. Ingeneral, housing 610 may include any suitable housing constructed of anysuitable material. In some examples, housing 610 may include a hardplastic, a metal, a glass, or the like. In general, antenna 620 mayinclude any suitable antenna or antennas suitable for the communicationstechniques discussed herein. In some examples, antenna 620 may beconfigured to receive a wide-band transmission transmitted from a basestation as discussed herein.

In general, analog-to-digital converter 630 and analog-to-digitalconverter 640 may include any suitable analog-to-digital converterdevice or devices. In some examples, analog-to-digital converter 640 mayhave an operating speed greater than an operating speed ofanalog-to-digital converter 630. In some examples, analog-to-digitalconverter 630 may have an operating speed of about 10 MSamples/sec andanalog-to-digital converter 640 may have an operating speed of about 100MSamples/sec. In general, processor 650 may include any suitableprocessor or processors such as, for example, a microprocessor, amulticore processor, or the like. In some examples, processor 650 may beconfigured to switch between analog-to-digital converter 630 andanalog-to-digital converter 640 so as to process the discusseddistributed traffic symbol portions and/or distributed pilot symbolportions of a wide-band transmission via analog-to-digital converter630, and so as to process the discussed intermittent punctured pilotsymbol portions of the wide-band transmission via analog-to-digitalconverter 640. Such example configurations may provide the discussedincreased sampling rates during the forming and/or evaluation ofpower-delay profiles discussed herein.

As discussed, in some examples, processor 650 may be configured toswitch between analog-to-digital converter 630 and analog-to-digitalconverter 640. In some examples, processor 650 may be configured toperform one or more of the techniques discussed herein and, inparticular, those techniques discussed with respect to method 400. Insome examples, processor 650 may be configured to determine a pathportion of a wide-band transmission based on the intermittent puncturedpilot symbol portions such that the path portion is associated with ashortest time delay of a multipath wide-band transmission. In someexamples, processor 650 may be configured to determine a distancebetween device 600 and a base station based on such a determined timedelay. In some examples, processor 650 may be configured to determine alocation of device 600 based on such a determined distance. In someexamples, processor 650 may be configured to determine a location ofdevice 600 based on a triangulation technique.

As discussed, in some examples, device 600 may include twoanalog-to-digital converters 630, 640 and processor 650 configured toselect one of analog-to-digital convertors 630, 640 for processing. Suchexamples may offer the advantages of lower power usage. In someexamples, a device may include one analog-to-digital converter having anoperating rate chosen such that a balance may be struck between accuracyin determining the location of the device and power usage. In someexamples, a device may include one analog-to-digital converter having avariable operating rate such that the analog-to-digital converter mayoperate a faster rate during the processing of intermittent puncturedpilot symbol portions of a wide-band transmission and slower during theprocessing of distributed traffic symbol portions and/or distributedpilot symbol portions of a wide-band transmission.

As discussed, in some examples, device 600 may include processorconfigured to select one of analog-to-digital convertors 630, 640 forprocessing. In some examples, a device may include a switch operablycoupled between antenna 620 and analog-to-digital convertors 630, 640such that the switch may selectively and operably couple one ofanalog-to-digital convertors 630, 640 to antenna 120. In some examples,a down-converter and/or a mixer may be operably coupled between antenna620 and analog-to-digital convertors 630, 640.

As discussed herein, profiles of multipath wide band transmissions maybe used to determine a time delay related to a shortest portion of themultipath. Such a determined time delay may be used to determine thelocation of the device. In some examples, the profile may be based onreceived intermittent punctured pilot symbol portions. Such intermittentpunctured pilot symbol portions may provide finer resolution in theprofiles of multipath wide band transmissions. In general, the greaternumber of intermittent punctured pilot symbol portions the moreinformation may be received allowing for greater averaging and reducednoise.

In general, the techniques discussed herein may be implemented in anysuitable device such as a laptop computer, a mobile phone, a smartphone,a netbook device, a tablet device, a personal digital assistant, or thelike. Such devices may receive, via a mobile device, a wide-bandtransmission having distributed traffic symbol portions, distributedpilot symbol portions, and intermittent punctured pilot symbol portionsfrom at least one base station of three or more base stations, determinea first path portion of the wide-band transmission associated with afirst time delay based on the intermittent punctured pilot symbolportions such that a second path portion of the wide-band transmissionis associated with a second time delay, determine a distance between themobile device and the at least one base station based on the first timedelay, or determine a location of the mobile device based on thedetermined distance, or the like.

As discussed, in some examples, the techniques discussed herein may beperformed at a base station, a host computer, a server, or the like,such that various processes in the discussed techniques may be offloadedfrom the mobile device. In some examples, a base station as discussedherein my be configured to provide a wide-band transmission as discussedherein and, in particular, a wide-band transmission as discussed withrespect to FIG. 5. In some examples, a base station may be configured totransmit a wide-band transmission including distributed traffic symbolportions, distributed pilot symbol portions, and intermittent puncturedpilot symbol portions.

FIG. 7 is an illustration of an example computer program product 700,arranged in accordance with at least some embodiments of the presentdisclosure. Computer program product 700 may include machine readablenon-transitory medium having stored therein a plurality of instructionsthat, when executed, cause the machine to provide web trackingprotection according to the processes and methods discussed herein.Computer program product 700 may include a signal bearing medium 702.Signal bearing medium 702 may include one or more machine-readableinstructions 704, which, when executed by one or more processors, mayoperatively enable a computing device to provide the functionalitydescribed herein. In some examples, machine-readable instructions 704may be provided as web browser software. In some examples,machine-readable instructions 704 may be provided as a web browserplug-in. In various examples, some or all of the machine-readableinstructions may be used by the devices discussed herein.

In some implementations, signal bearing medium 702 may encompass acomputer-readable medium 706, such as, but not limited to, a hard diskdrive, a Compact Disc (CD), a Digital Versatile Disk (DVD), a digitaltape, memory, etc. In some implementations, signal bearing medium 702may encompass a recordable medium 708, such as, but not limited to,memory, read/write (R/W) CDs, R/W DVDs, etc. In some implementations,signal bearing medium 702 may encompass a communications medium 710,such as, but not limited to, a digital and/or an analog communicationmedium (e.g., a fiber optic cable, a waveguide, a wired communicationlink, a wireless communication link, etc.). In some examples, signalbearing medium 702 may encompass a machine readable non-transitorymedium.

FIG. 8 is a block diagram illustrating an example computing device 800,arranged in accordance with at least some embodiments of the presentdisclosure. In various examples, computing device 800 may be configuredto determine the location of a device in an indoor environment asdiscussed herein. In one example basic configuration 801, computingdevice 800 may include one or more processors 810 and system memory 820.A memory bus 830 can be used for communicating between the processor 810and the system memory 820.

Depending on the desired configuration, processor 810 may be of any typeincluding but not limited to a microprocessor (μP), a microcontroller(μC), a digital signal processor (DSP), or any combination thereof.Processor 810 can include one or more levels of caching, such as a levelone cache 811 and a level two cache 812, a processor core 813, andregisters 814. The processor core 813 can include an arithmetic logicunit (ALU), a floating point unit (FPU), a digital signal processingcore (DSP Core), or any combination thereof. A memory controller 815 canalso be used with the processor 810, or in some implementations thememory controller 815 can be an internal part of the processor 810.

Depending on the desired configuration, the system memory 820 may be ofany type including but not limited to volatile memory (such as RAM),non-volatile memory (such as ROM, flash memory, etc.) or any combinationthereof. System memory 820 may include an operating system 821, one ormore applications 822, and program data 824. Application 822 may includelocation determination application 823 that can be arranged to performthe functions, actions, and/or operations as described herein includingthe functional blocks, actions, and/or operations described herein.Program Data 824 may include location determination data 825 for usewith location determination application 823. In some exampleembodiments, application 822 may be arranged to operate with programdata 824 on an operating system 821. This described basic configurationis illustrated in FIG. 8 by those components within dashed line 801.

Computing device 800 may have additional features or functionality, andadditional interfaces to facilitate communications between the basicconfiguration 801 and any required devices and interfaces. For example,a bus/interface controller 840 may be used to facilitate communicationsbetween the basic configuration 801 and one or more data storage devices850 via a storage interface bus 841. The data storage devices 850 may beremovable storage devices 851, non-removable storage devices 852, or acombination thereof. Examples of removable storage and non-removablestorage devices include magnetic disk devices such as flexible diskdrives and hard-disk drives (HDD), optical disk drives such as compactdisk (CD) drives or digital versatile disk (DVD) drives, solid statedrives (SSD), and tape drives to name a few. Example computer storagemedia may include volatile and nonvolatile, removable and non-removablemedia implemented in any method or technology for storage ofinformation, such as computer readable instructions, data structures,program modules, or other data.

System memory 820, removable storage 851 and non-removable storage 852are all examples of computer storage media. Computer storage mediaincludes, but is not limited to, RAM, ROM, EEPROM, flash memory or othermemory technology, CD-ROM, digital versatile disks (DVD) or otheroptical storage, magnetic cassettes, magnetic tape, magnetic diskstorage or other magnetic storage devices, or any other medium which maybe used to store the desired information and which may be accessed bycomputing device 800. Any such computer storage media may be part ofdevice 800.

Computing device 800 may also include an interface bus 842 forfacilitating communication from various interface devices (e.g., outputinterfaces, peripheral interfaces, and communication interfaces) to thebasic configuration 801 via the bus/interface controller 840. Exampleoutput interfaces 860 may include a graphics processing unit 861 and anaudio processing unit 862, which may be configured to communicate tovarious external devices such as a display or speakers via one or moreNV ports 863. Example peripheral interfaces 870 may include a serialinterface controller 871 or a parallel interface controller 872, whichmay be configured to communicate with external devices such as inputdevices (e.g., keyboard, mouse, pen, voice input device, touch inputdevice, etc.) or other peripheral devices (e.g., printer, scanner, etc.)via one or more I/O ports 873. An example communication interface 880includes a network controller 881, which may be arranged to facilitatecommunications with one or more other computing devices 883 over anetwork communication via one or more communication ports 882. Acommunication connection is one example of a communication media.Communication media may typically be embodied by computer readableinstructions, data structures, program modules, or other data in amodulated data signal, such as a carrier wave or other transportmechanism, and may include any information delivery media. A “modulateddata signal” may be a signal that has one or more of its characteristicsset or changed in such a manner as to encode information in the signal.By way of example, and not limitation, communication media may includewired media such as a wired network or direct-wired connection, andwireless media such as acoustic, radio frequency (RF), infrared (IR) andother wireless media. The term computer readable media as used hereinmay include both storage media and communication media.

Computing device 800 may be implemented as a portion of a small-formfactor portable (or mobile) electronic device such as a cell phone, amobile phone, a tablet device, a laptop computer, a personal dataassistant (PDA), a personal media player device, a wireless web-watchdevice, a personal headset device, an application specific device, or ahybrid device that includes any of the above functions. Computing device800 may also be implemented as a personal computer including both laptopcomputer and non-laptop computer configurations. In addition, computingdevice 800 may be implemented as part of a wireless base station orother wireless system or device.

Some portions of the foregoing detailed description are presented interms of algorithms or symbolic representations of operations on databits or binary digital signals stored within a computing system memory,such as a computer memory. These algorithmic descriptions orrepresentations are examples of techniques used by those of ordinaryskill in the data processing arts to convey the substance of their workto others skilled in the art. An algorithm is here, and generally, isconsidered to be a self-consistent sequence of operations or similarprocessing leading to a desired result. In this context, operations orprocessing involve physical manipulation of physical quantities.Typically, although not necessarily, such quantities may take the formof electrical or magnetic signals capable of being stored, transferred,combined, compared or otherwise manipulated. It has proven convenient attimes, principally for reasons of common usage, to refer to such signalsas bits, data, values, elements, symbols, characters, terms, numbers,numerals or the like. It should be understood, however, that all ofthese and similar terms are to be associated with appropriate physicalquantities and are merely convenient labels. Unless specifically statedotherwise, as apparent from the following discussion, it is appreciatedthat throughout this specification discussions utilizing terms such as“processing,” “computing,” “calculating,” “determining” or the likerefer to actions or processes of a computing device, that manipulates ortransforms data represented as physical electronic or magneticquantities within memories, registers, or other information storagedevices, transmission devices, or display devices of the computingdevice.

The foregoing detailed description has set forth various embodiments ofthe devices and/or processes via the use of block diagrams, flowcharts,and/or examples. Insofar as such block diagrams, flowcharts, and/orexamples contain one or more functions and/or operations, it will beunderstood by those within the art that each function and/or operationwithin such block diagrams, flowcharts, or examples can be implemented,individually and/or collectively, by a wide range of hardware, software,firmware, or virtually any combination thereof. In some embodiments,several portions of the subject matter described herein may beimplemented via Application Specific Integrated Circuits (ASICs), FieldProgrammable Gate Arrays (FPGAs), digital signal processors (DSPs), orother integrated formats. However, those skilled in the art willrecognize that some aspects of the embodiments disclosed herein, inwhole or in part, can be equivalently implemented in integratedcircuits, as one or more computer programs running on one or morecomputers (e.g., as one or more programs running on one or more computersystems), as one or more programs running on one or more processors(e.g., as one or more programs running on one or more microprocessors),as firmware, or as virtually any combination thereof, and that designingthe circuitry and/or writing the code for the software and or firmwarewould be well within the skill of one of skill in the art in light ofthis disclosure. In addition, those skilled in the art will appreciatethat the mechanisms of the subject matter described herein are capableof being distributed as a program product in a variety of forms, andthat an illustrative embodiment of the subject matter described hereinapplies regardless of the particular type of signal bearing medium usedto actually carry out the distribution. Examples of a signal bearingmedium include, but are not limited to, the following: a recordable typemedium such as a flexible disk, a hard disk drive (HDD), a Compact Disc(CD), a Digital Versatile Disk (DVD), a digital tape, a computer memory,etc.; and a transmission type medium such as a digital and/or an analogcommunication medium (e.g., a fiber optic cable, a waveguide, a wiredcommunication link, a wireless communication link, etc.).

The herein described subject matter sometimes illustrates differentcomponents contained within, or connected with, different othercomponents. It is to be understood that such depicted architectures aremerely examples and that in fact many other architectures can beimplemented which achieve the same functionality. In a conceptual sense,any arrangement of components to achieve the same functionality iseffectively “associated” such that the desired functionality isachieved. Hence, any two components herein combined to achieve aparticular functionality can be seen as “associated with” each othersuch that the desired functionality is achieved, irrespective ofarchitectures or intermedial components. Likewise, any two components soassociated can also be viewed as being “operably connected”, or“operably coupled”, to each other to achieve the desired functionality,and any two components capable of being so associated can also be viewedas being “operably couplable”, to each other to achieve the desiredfunctionality. Specific examples of operably couplable include but arenot limited to physically mateable and/or physically interactingcomponents and/or wirelessly interactable and/or wirelessly interactingcomponents and/or logically interacting and/or logically interactablecomponents.

With respect to the use of substantially any plural and/or singularterms herein, those having skill in the art can translate from theplural to the singular and/or from the singular to the plural as isappropriate to the context and/or application. The varioussingular/plural permutations may be expressly set forth herein for sakeof clarity.

It will be understood by those within the art that, in general, termsused herein, and especially in the appended claims (e.g., bodies of theappended claims) are generally intended as “open” terms (e.g., the term“including” should be interpreted as “including but not limited to,” theterm “having” should be interpreted as “having at least,” the term“includes” should be interpreted as “includes but is not limited to,”etc.). It will be further understood by those within the art that if aspecific number of an introduced claim recitation is intended, such anintent will be explicitly recited in the claim, and in the absence ofsuch recitation no such intent is present. For example, as an aid tounderstanding, the following appended claims may contain usage of theintroductory phrases “at least one” and “one or more” to introduce claimrecitations. However, the use of such phrases should not be construed toimply that the introduction of a claim recitation by the indefinitearticles “a” or “an” limits any particular claim containing suchintroduced claim recitation to inventions containing only one suchrecitation, even when the same claim includes the introductory phrases“one or more” or “at least one” and indefinite articles such as “a” or“an” (e.g., “a” and/or “an” should typically be interpreted to mean “atleast one” or “one or more”); the same holds true for the use ofdefinite articles used to introduce claim recitations. In addition, evenif a specific number of an introduced claim recitation is explicitlyrecited, those skilled in the art will recognize that such recitationshould typically be interpreted to mean at least the recited number(e.g., the bare recitation of “two recitations,” without othermodifiers, typically means at least two recitations, or two or morerecitations). Furthermore, in those instances where a conventionanalogous to “at least one of A, B, and C, etc.” is used, in generalsuch a construction is intended in the sense one having skill in the artwould understand the convention (e.g., “a system having at least one ofA, B, and C” would include but not be limited to systems that have Aalone, B alone, C alone, A and B together, A and C together, B and Ctogether, and/or A, B, and C together, etc.). In those instances where aconvention analogous to “at least one of A, B, or C, etc.” is used, ingeneral such a construction is intended in the sense one having skill inthe art would understand the convention (e.g., “a system having at leastone of A, B, or C” would include but not be limited to systems that haveA alone, B alone, C alone, A and B together, A and C together, B and Ctogether, and/or A, B, and C together, etc.). It will be furtherunderstood by those within the art that virtually any disjunctive wordand/or phrase presenting two or more alternative terms, whether in thedescription, claims, or drawings, should be understood to contemplatethe possibilities of including one of the terms, either of the terms, orboth terms. For example, the phrase “A or B” will be understood toinclude the possibilities of “A” or “B” or “A and B.”

While certain example techniques have been described and shown hereinusing various methods and systems, it should be understood by thoseskilled in the art that various other modifications may be made, andequivalents may be substituted, without departing from claimed subjectmatter. Additionally, many modifications may be made to adapt aparticular situation to the teachings of claimed subject matter withoutdeparting from the central concept described herein. Therefore, it isintended that claimed subject matter not be limited to the particularexamples disclosed, but that such claimed subject matter also mayinclude all implementations falling within the scope of the appendedclaims, and equivalents thereof.

1. A method, comprising: receiving, via a mobile device, a wide-bandtransmission transmitted from at least one base station of three or morebase stations, wherein the wide-band transmission includes distributedtraffic symbol portions, distributed pilot symbol portions, andintermittent punctured pilot symbol portions; determining, via themobile device, a first path portion of the wide-band transmission basedat least in part on the intermittent punctured pilot symbol portions,wherein the first path portion of the wide-band transmission isassociated with a first time delay and a second path portion of thewide-band transmission is associated with a second time delay;determining, via the mobile device, a distance between the mobile deviceand the at least one base station based at least in part on the firsttime delay; and determining, via the mobile device, a location of themobile device based at least in part on the determined distance.
 2. Themethod of claim 1, wherein the intermittent punctured pilot symbolportions comprises pilot symbols being simultaneously transmitted acrossat least a majority of frequencies of the wide-band transmission.
 3. Themethod of claim 1, wherein the intermittent punctured pilot symbolportions comprise puncturing from a rate of about one punctured pilotsymbol in five hundred traffic symbols to a rate of about one puncturedpilot symbol in five thousand traffic symbols.
 4. The method of claim 1,wherein determining the location of the mobile device comprisesdetermining the position of the mobile device based at least in part onposition data having predetermined position information associated withthe at least one base station that is transmitted by the at least onebase station at predetermined times.
 5. The method of claim 1, whereinthe wide-band transmission comprises from about 2⁹ sinusoidalsub-carriers to about 2¹⁵ sinusoidal sub-carriers.
 6. The method ofclaim 1, wherein the determination of the first path portion is based atleast in part on a power-delay profile.
 7. The method of claim 1,wherein the determination of the first path portion is based at least inpart on a Multiple Signal Classification (MUSIC) algorithm.
 8. Themethod of claim 1, wherein the determination of the first path portionis based at least in part on an algorithm capable ofsuper-resolvability.
 9. The method of claim 1, wherein the determinationof the first path portion comprises a first and a second determinationof the first path portion, wherein the second determination of the firstpath portion samples only up to and including an earliest path portionidentified by the first determination of the first path portion and hasa finer sampling as compared with the first determination of the firstpath portion.
 10. The method of claim 1, wherein the intermittentpunctured pilot symbol portions comprises pilot symbols beingsimultaneously transmitted across at least a majority of frequencies ofthe wide-band transmission from a rate of about one punctured pilotsymbol in five hundred traffic symbols to a rate of about one puncturedpilot symbol in five thousand traffic symbols; wherein determining thelocation of the mobile device includes determining the position of themobile device based at least in part on position data havingpredetermined position information associated with the at least one basestation that is transmitted by the at least one base station atpredetermined times; wherein the wide-band transmission comprises fromabout 2⁹ sinusoidal sub-carriers to about 2¹⁵ sinusoidal sub-carriers;and wherein the determination of the first path portion is based atleast in part on a power-delay profile and on an algorithm capable ofsuper-resolvability, wherein the determination of the first path portioncomprises a first and a second determination of the first path portion,and wherein the second determination of the first path portion samplesonly up to and including an earliest path portion identified by thefirst determination of the first path portion and has a finer samplingas compared with the first determination of the first path portion. 11.A mobile handset apparatus, comprising: a housing; an antenna locatedwithin the housing; a first analog-to-digital converter operably coupledto the antenna; a second analog-to-digital converter operably coupled tothe antenna, wherein the second analog-to-digital converter has anoperating speed greater than the first analog-to-digital converter; anda processor operably coupled to the first and second analog-to-digitalconverters; wherein the processor is configured to switch between thefirst and second analog-to-digital converters so as to processdistributed traffic symbol portions and/or distributed pilot symbolportions of a wide-band transmission transmitted from at least one basestation of three or more base stations via the first analog-to-digitalconverter, and so as to process intermittent punctured pilot symbolportions of the wide-band transmission via the second analog-to-digitalconverter.
 12. The apparatus of claim 11, wherein the processor isfurther configured to: determine a first path portion of the wide-bandtransmission based at least in part on the intermittent punctured pilotsymbol portions, wherein the first path portion of the wide-bandtransmission is associated with a first time delay and a second pathportion of the wide-band transmission is associated with a second timedelay; determine a distance between the mobile device and the at leastone base station based at least in part on the first time delay; anddetermine a location of the mobile device based at least in part on thedetermined distance.
 13. The apparatus of claim 12, wherein theintermittent punctured pilot symbol portions comprises pilot symbolsbeing simultaneously transmitted across at least a majority offrequencies of the wide-band transmission.
 14. The apparatus of claim12, wherein the intermittent punctured pilot symbol portions comprisepuncturing from a rate of about one punctured pilot symbol in fivehundred traffic symbols to a rate of about one punctured pilot symbol infive thousand traffic symbols.
 15. The apparatus of claim 12, whereinthe location of the mobile device is determined based at least in parton position data having predetermined position information associatedwith the at least one base station that is transmitted by the at leastone base station at predetermined times.
 16. The apparatus of claim 12,wherein the wide-band transmission comprises from about 2⁹ sinusoidalsub-carriers to about 2¹⁵ sinusoidal sub-carriers.
 17. The apparatus ofclaim 12, wherein the determination of the first path portion is basedat least in part on a power-delay profile.
 18. The apparatus of claim12, wherein the determination of the first path portion is based atleast in part on an algorithm capable of super-resolvability.
 19. Theapparatus of claim 12, wherein the determination of the first pathportion comprises a first and a second determination of the first pathportion, wherein the second determination of the first path portionsamples only up to and including an earliest path portion identified bythe first determination of the first path portion and has a finersampling as compared with the first determination of the first pathportion.
 20. An article comprising: a signal bearing medium comprisingmachine-readable instructions stored thereon, which, if executed by oneor more processors, operatively enable a computing device to: receive awide-band transmission transmitted from at least one base station ofthree or more base stations, wherein the wide-band transmission includesdistributed traffic symbol portions, distributed pilot symbol portions,and intermittent punctured pilot symbol portions; determine a first pathportion of the wide-band transmission based at least in part on theintermittent punctured pilot symbol portions, wherein the first pathportion of the wide-band transmission is associated with a first timedelay and a second path portion of the wide-band transmission isassociated with a second time delay; determine a distance between themobile device and the at least one base station based at least in parton the first time delay; and determine a location of the mobile devicebased at least in part on the determined distance.
 21. The article ofclaim 20, wherein the intermittent punctured pilot symbol portionscomprises pilot symbols being simultaneously transmitted across at leasta majority of frequencies of the wide-band transmission from a rate ofabout one punctured pilot symbol in five hundred traffic symbols to arate of about one punctured pilot symbol in five thousand trafficsymbols; wherein the location of the mobile device is determined basedat least in part on position data having predetermined positioninformation associated with the at least one base station that istransmitted by the at least one base station at predetermined times;wherein the wide-band transmission comprises from about 2⁹ sinusoidalsub-carriers to about 2¹⁵ sinusoidal sub-carriers; and wherein thedetermination of the first path portion is based at least in part on apower-delay profile and on an algorithm capable of super-resolvability,wherein the determination of the first path portion comprises a firstand a second determination of the first path portion, and wherein thesecond determination of the first path portion samples only up to andincluding an earliest path portion identified by the first determinationof the first path portion and has a finer sampling as compared with thefirst determination of the first path portion.